Telephone system



NOV. 14, w H w TE TELEPHONE SYSTEM Filed Jan. 7, 1938 2 Sheets-Sheet 2 BY ,W%YW

AT RNEY tem accordingly not only would decrease cost For a more complete understanding of the r and materials and simplify installation and invention, reference may be had to the accoml5 servicing, but would also render the system much panying drawings in which: more fiexibleand enable the use of a greater Figure 1 is a schematic electrical diagram of number of su 'tations when required. one form of the telephone system of this inven- A system of this general nature, in which a tion; considerable saving of wire is effected with many Fig. 2 is a simplified schematic diagram of the calls. simultaneously engage springs l3 and I6, respec- 50 Patented Nov. 14, 1939 i I V UNITED STATES PATENT orrics TELEPHONE SYSTEM William H. Waite, Lynbrook, N. Y., assignor to Dictograph Products Company, Inc., New York, N. Y., a corporation of Delaware Application January 7, 1938, Serial No. 183,74;

10 Claims. (01. 119-39) This. invention relates to telephone systems the master station. Two relays, each individual and has particular referenceto intercommunito the corresponding master and substation are eating telephone systems in which a master stainterposed in each said single conductor and are tion may communicate with any one of a numenergized upon operation of either a substation 5 her of substations and any substation may comor corresponding master station calling switch to 5 municate with the master station. temporarily break the normal talking circuit, As the number of substations is increased the which is immediately restored 'and completed wiring increases proportionately, thus greatly inwhen the answering station responds, this arcreasing cost, materials, and installation and rangement enabling the simplification efl'ected by servicing problems andplacing a practical limit the reduced wiring. Secrecy provisions are made 10 on the number of substations- Any means for and other improvements are included which augdecreasing the amount of necessary wiring withment the efficiency and operating facility of the out impairing the operation facility of the syssystem.

of the attendant advantages enumerated, is distelephonic circuit;

closed in Patent No. 2,007,990, issued July 16, Fig.3isafragmentary schematic electricaldia- 1935, to William H. Waite. That system is degram of an optional form of substation circuit; scribed as particularly applicable to a hospital and l '25 telephone system, although not limited to that Fig. 4 is a fragmentary schematic diagram of use, and requires only one conductor between the an adaptation of the master station circuit. :master station and each of the substations with Referring to Figure 1, the master station is a switching control relay, in addition to the necesdesignated M and the substations, of which there sary common conductors, thus effecting a wire may be any desirable number, such as the tour so saving of approximately 45%. However, in hosshown, are designated A, B, C and D. The master .pital systems a call is initiated by the patient station M is provided with corresponding suband is completed by the master station for obvistation keys or switches a, b, c and d, with their ops reasons, no provision being made for initiacorresponding visual signal fiags or other indition of the call from the master station, except cators (11, b1, 01 and da- Inasmuch as the subby signal responded to by the patient, who then stations are identical, the description of one of 35 actually initiates the call, so that while there may them, A, will suffice. be direct intercommunication between the mas- Substation A includes a transmitter or microter station and substation, the facility provided phone i0, a receiver II, either separate or handby two-way initiation of calls is lacking in such set type, and a key-operated switch l2, either so system. directly manually operable or operable by move- 40 In accordance with the present invention an ment of the receiver or handset. Substation intercommunicating telephone system is provided switch l2 consists of two sides or parts, one of for two-way initiation of calls between a master which has five contact springs and the other four. station and any one of a plurality of substations, The former comprises a spring l3 normally diswhich embodies the advantages of minimum wirengaged from spring ,which normally engages 45 mg and attendant saving of first and installation spring ii. A fourth spring I6 is normally discost and labor of the system of the aforemenengaged from a fifth spring I]. Springs l4 and tioned patent, and also has all of the operating l'l are connected by an insulating bar 10 so that advantages aflorded by two-way initiation of when switch I! is operated, the springs l4 and 11 In a preferred embodiment of the invention, tively, and spring I4 disengages spring 15. The

each substation is connected to the master staother side of the substation switch I! includes tion by only onesingle conductor which is indicontact springs 20 and 22 which are normally dis- .vidual to that substation and is additional to the engaged from contact springs l9 and 2|, respeccommon conductors between all substations and tively, connected by insulating bar 33 .for simul- 55 a common positive line 12 is connected by wire 46 to '58 of corresponding signal flag a1 wire 35 connected to contact spring I 8.

taneous operation when the key is manipulated to engage switch contacts 28 and 22, respectively.

First contact spring l3 of substation key switch the common positive line 45, while second contact spring I4 is connected by wire 24 to local relay 25, the other side 01' which is connected by wire 49 through relay at the master station M, and wire 5| to switch contact 52 of the corresponding master station key a. This contact 52 normally engages contact 53 which is connected by wire 55 to common negative line 44.

The third contact spring I 5 of the substation switch I2 is connected by wire 43 to the common negative line 44, while fourthcontact spring I6 is connected by wire 48 to relay 25 contact spring 33, which normally engages contact spring 34, connected by wire 4| to a talking line 42 which is common to both the substations and the master station.

The fifth spring I1 is connected by wire 38 through the local transmitter or microphone II to contact spring 22 on the other side of the substation key. The talking circuit of transmitter |8 also traverses the substation receiver I I through Contact spring 2| is connected by wire 89 to the common negative line 44L Contact spring 28 is connected by wire 36 to relay contact spring 28 engaging contact spring 32, connected by wire 31 to common talking line 38. I

Relay 25 contact spring 38 is insulated by block 29 from contact spring 28, and is normally disengaged from cooperating contact spring 3| connected through buzzer 48 by wire 41 to one side of relay 25 coil. Contact spring 38 is connected through resistor 88 and wire 98 to common positive line 45. The armature 28 of relay 25 is connected by insulating bar 21 to contact spring 28 so that armature 26 and spring 28 operate as a unit.

The individual substations A, B, C and D are each provided with the single direct wire 49 which, like wire 49 of station A, is connected to a reIay at the master station corresponding to the substation. The wires 43, 46', 4|, 31', 89','and 98', on substations B, C, and D correspond to the wires 43, 46, 4|, 31, 89, and 98 of substation A.

The master station key switch a contact spring 52 is adapted to engage contact spring 54 connected through wire 83, relay 12 and wire 89 to 45. Key switch a contact spring 51 is adapted to engage spring 58, which completes a circuit from common negative line 44, normally engaged springs 8| and 59, wire 58, spring 58, spring 51, wire 18, relay 1| and wire 89 to common positive line 45.

When flag relay 58 is energized, its armature 81, connected by insulating block 68 to spring 8| disengages spring 8| from spring 59 and engages it with spring 82. This completes a circuit from common negative line 44, through springs 8| and 62, wire 83, normally closed switch 64, wire 65, normally closed spring contacts 86 and 61, local buzzer 68 and wire 69 to common positive line 45, between which and common positive line 44 is connected the signal battery 83. The buzzer 68, thus energized, signals the master station that it is being signalled and raised flag 111 indicates the calling substation.

When the relay 1| is energized, its armature 16 mon talking line 42 through the armature 16, contact spring 15, wire 11, impedance or choke coil 18, and wire 19 to the positive terminal of which is connected common talking line engages a contact spring 15, connecting com- 88, the negative terminal to common negative wire 44. The .master station receiver 88, which is preferably a loud speaker, is connected in series with a condenser 85, and both are connected in parallel with impedance coil 18.

Energization of relay 1| also causes its armsture 18 to engage contact spring 13 with contact spring 14 to complete-a circuit from common talking line 38 through engaged contact springs 13 and 14, wire 8|, local transmitter or microphone 82, and wire 19 to talking battery 88.

In operation of the arrangement 0! Fig. 1, and assuming that A desires to communicate with the master station M, the substation key I2 is manipulated, completing a circuit traceable from common positive line 45, wire 48, contact l3, contact spring |4, wire 24, local relay 25, wire 48, substation flag m relay 58, wire 5|, switch key a closed contacts 52 and 53, wire 58 and common negative line 44, thus energizing the respective substation and master station relays 25 and 88. Armature 81 of called master station relay 58 raises flag a1 indicating the calling substation A and causes the spring 8| to disengage contact 88 and engage contact 82, thus. completing a circuit from the common negative line 44, spring 8|. contact 82, wire 83, closed switch 84, wire 88, contact 88, armature 81 of the relay 12, buzzer 88 and wire 89 to common positive line 45, thus energizing the master station buzzer 88, which may be silenced by opening switch 64.

Energizing of calling substation A relay 28 breaks the normal talking circuit between the microphone or transmitter l8 and common talking line 42, by disengaging contacts 33 and 34. Similarly, the normal listening circuit between the substation receiver II and common talking line 38 is broken by the disengagement of contacts 28 and 32 by relay 25. When the master station responds by manipulating the key a corresponding to raised flag m, the talking and listening circuits are reestablished by the deenergized relays 25 and 58, due to reengagement of relay 25 contacts 33 and 34 and 28 and 32. Key a also disengages contacts 52 and 53, resetting flag relay 58 and breaking the buzzer 88 circuit through contacts 8| and 82.

Simultaneously spring 8| engages contact 59, completing a circuit traceable from common negative line 44 through spring 6|, contact 89, wire 58, contact 58, spring 51, wire 18, relay 11, wire 89 and common positive line 45. Relay 1| armature 16 engages contact 15 and also causes of the talking batte y engagement of spring 13 and contact 14, so that r the master station receiver 88 is connected to transmitter 82 is connected to common talking line 38. The master station talking or sub-station listening circuit is now completed from common negative line 44 through the talking battery 88: wire 19, master station microphone or transmitter 82, wire 8|, contacts 13 and 14, common talking line 38, wire 31, spring contacts 32 and 28, wire 36, spring contacts 28 and I8, wire 35, sub-station receiver contacts 22 and. 2|, and wire 89 back to common negative line 44.

The sub-station talking or master station listening circuit is traceable from common negative line 44, talking battery 88, wire 19, parallel impedance coil 18 and receiver 86 and condenser 85, wire 11, contacts 15 and 18, common talking line 42, wire 4|, contacts 34 and 33, wire 48, contacts l8 and I1, wire 39, sub-station microphone 42, and master station.

or transmitter l0, contacts 22 and II and wire 88 back to common negative line 44.

The restoration of the keys or switches at the master station and sub-station restores the circuits to their normal inoperative condition.

Assuming that master station M wishes to call a sub-stationsuch as A, manipulation of key it engages spring 52 with contact 54, completing a signalling circuit traceable from common positive line 45, wire 89, relay 12, wire 83, contacts 54 and 52, wire 5|, flag a'i relay 50, wire 49, substation relay 25, wire 24, contacts l4 and I5 and 'wire 43 to common negative line 44. The relays 25 and 50 are energized as before, breaking both normal talking circuits. The armature 28 of the relay 25 actuates spring 28 to engage contact 30 with 3| through the insulating piece 29.. This closes a signalling circuit from common positive line 45, wire 90, resistor 88, contacts 30 and 3|,

the sub-station buzzer 48, wires 41 and 24,'contacts l4 and I5 and wire 43 to common negative line 44, thus energ zing the buzzer 48. Manipulation of sub-station key |2 breaks the contact between H and I5, and engages contacts l3 and I4, thus simultaneously deenergizing the substation buzzer 48, and the two relays 25 and 50. This reestablishes the two talking circuits as described between the two stations.

It will be observed that the normal talking and listening circuits of the sub-station are first broken by relay 25 and then restored by deenergization thereof when thetalking and listening circuits are completed, thus effecting the saving in wire heretofore described. Another important feature is that conversation between any sub-station and the master station is entirely secret. If a second sub-station switch is operated while the master station and a sub-station circuits are completed it will act to operate the relays 25 and 50 in the single line 49 to the master station, thus energiz ng the master station buzzer 88 and also disconnecting that station from the talking lines 38 and 42. The talking circuit remains disconnected due to this interrupton until the operator at the master station operates the key corresponding to the second sub-station to reclose the circuit and communication may proceed.

Fig. 2 illustrates the simplified talking circuit in which the substation receiver H and the mas- ,ter station transmitter 82 are in series. while the substation transmitter l0 and the master station receiver 88 are also inseries. the talking battery 00 being common to both circuits. The imped ance coil 18 permits the flow of direct current, but has a high impedance to the voice currents, while the condenser 85 prevents the flow of direct current through the loud speaker 88 and at the same time offers very low impedance to the'voice currents. Thus, direct current is kept out of the loud speaker 88, and most of the voice current is shunted through it.

Fig. 3 illustrates the use of the receiver hook as the key to actuate the switch l2 at the substation. The circuit is the same as in Fig. i with the exception that the spring I! is replaced by the receiver hook I04. The receiver H with the microphone or transmitter l0 may also be combined in a hand set, in which case hook |04 may be a handset cradle. The removal of the receiver or handset from the hook I04, energizes the relays 25 and 50 in the same manner as when the key i2 is manually manipulated. Similarly, replacement of the receiver or handset on the hook 8|, through spring 92 to their normal inop- ||l4 restores all the circuits erative position. Fig. 4 illustrates an alternative arrangement at the master station for disconnecting the loud speaker 85 and the microphone or transmitter 82 and substituting a hand set for private conversation. For loud speaker operation the talking circuit includes the usual wire 11 from talking line 42, spring 95 normally engaging contact 98, a wire 99, the microphone or transmitter 82, the talking battery and the negative line 44. The listening circuit is traced from common talking wire 38, wire 8|, through a spring 92 normally engaging contact 9|, wire I00, an impedance coil 18, in parallelwith condenser and the loud speaker 88, and talking battery 80 to common negative line 44. For private conversation the handset is removed from the hook |0|, thus breaking the loud speaker circuit and. establishing the new handset circuit. In this case, the transmitter circuit is traced from wire 11, spring 95, contact 94, wire I02, the private transmitter or microphone 98 and talking battery 80 to the negative line 44. The receiver wire I03, the private'receiver 91 tery 80 to the negative line 44.

It will be seen that the new telephone system requires a minimum of wiring, while at the same and talking battime it insures complete privacy in communication between any substation tion. Not only is it possi signal and converse with it is possible for and the master stale for a sub-station to the master station, but the master station to signal and converse with any one of the sub-stations without being overheard through another sub-station receiver.

While a specific embodiment has been presented in this application it is to be understood that the invention is not to be limited in any way thereby except as defined in the claims.

I claim:

1. In a telephone system, the combination of a master station, a plurality of substations, a plurality of conductors each connected to each substation and to the master station, a single conductor between each substation and the master station individual only to those substations, two relays in each said single conductor individual to the master station and the corresponding substation, a telephone instrument at the master station controlled by the corresponding relay, a telephone instrument at each substation controlled by the corresponding relay, and a switch in each said single conductor for operating the corresponding relays.

2. In a telephone system, the combination of a master station having a telephone instrument, a plurality of substations each having a telephone instrument, a plurality of conductors each connected to each substation and to the master station, a single conductor between each substation instrument and the master station instrument which is individual only to those instruments, two relays in each said single conductor, one of said relays being individual to the master station instrument for controlling the same and the other relay being individual to the corresponding substation for controlling the corresponding instrument, and a switch at the master station for operating the corresponding relays.

3. In a telephone system, the combination of a master station having a telephone instrument, a plurality of substations each having a telephone instrument, a plurality of conductors each concircuit is traced from wire I engaging the contact 93,

u: on

nected to each substation and to the master station, a single conductor between each substation instrument and the master station instrument which is individual only to those instruments, two relays in each said single conductor, one of said relays being individual to the master station instrument for controlling the same and the other relay being individual to corresponding substation for controlling the corresponding instrument, and a switch at each substation for operating the corresponding relays.

4. In a telephone system, master station having a telephone instrument, a plurality of substations each having a telephone instrument, a plurality of conductors eachconnected to each substation and to the master station, a single conductor between each substation instrument and the master station instrument which is individual only to those instruments, two relays in each said single conductor, one of said relays being individual to the master station instrument for controllingthe same and the other relay being individual to corresponding substation for controlling the corresponding instrument, and switches at the substations and the master station for the operation of the corresponding relays.

5. In a telephone system, the combination of a master station having a telephone instrument, a plurality of substations each having a telephone instrument, a plurality of conductors each connected to each substation and to the master station, a single conductor between each substation instrument and the master station instrument which is individual only to those instruments, two relays in the said single conductor of each substation, operative connections between one of said relays and the master station in strument for controlling the latter, a second telephone instrument at each substation controlled by the corresponding second relay, and a switch for operating the relays.

6. In a telephone system, the combination oi. a master station having a telephone instrument, a plurality of substations each having a telephone instrument, a plurality of conductors each connected to each substation and to the master station, a single conductor between each substation instrument and the master station instrument which is individual only to those instruments, two relays in the said single conductor of each substation, operative connections between one of said relays and the master station instrument for controlling the latter, a second telephone instrument at such substation controlled by the corresponding second relay, and a switch at the master station for operating the relays.

'7. In a telephone system, the combination of nected to each substation and the combination of a a master station having a telephone instrument, a plurality oi'substations each having a telephone instrument, a plurality of conductors each canto the master station, a single conductor between each substation instrument and the master station instrument which is individual only to those instruments, two relays in the said single conductor of each substation, a second telephone instrument at each substation controlled by the corresponding relay, a switch in each said single conductor for-operating the corresponding relays, and a second telephone instrument at the master station connectible to the second instrument. at a substation by the corresponding relay upon operation of the corresponding switch.

8. In a telephone system, the combination of a master station having telephone instruments, a plurality of substations each having telephone instruments, a normally closed circuit for each substation instrument, a relay controlling said circuit, a switch for actuating said relay to break the normal circuit of at least one of the substation instruments, and a switch for restoring said relays to restore the normal circuit of said one substation instrument and establish a communication circuit between the said substation and master station instruments.

9. In a telephone system, the combination of a master station having telephone instrument's, a plurality of substations each having telephone instruments, a normally closed circuit for each substation instrument, arelay controlling said circuit, a switch at the master station for actuating said relay to break the normal circuit of at least one of the corresponding substation instruments, and a switch at the substation for restoring said relay. to restore the normal circuit of said one substation instrument and establish a communication circuit between the said master station instruments.

10. In a telephone system, the combination of. a master station having telephone instruments, a plurality of substations each having telephone instruments, a normally closed circuit for each substation instrument, relays at the substations controlling the circuits of the corresponding instruments, switches at the substation and the master station for actuating the corresponding relay to break the normal circorresponding relay to restore the normal circuit of said one substation instrument and establish a communication circuit between the said master station and substation instrument.

WILLIAM H. WAITE.

substation and i CERTIFICATE 'OF CORRECTION. Patent no 2,179,652. November M91939.

WILLIAM H. WAITE. Itgis hereby certified that error appears in the printed specification of'the above numbered patent reqdiring correction as follows: Page first column, line 5b,, claim 6, for the word "such" read each; and that the said Letters Patent should be read with this correction therein that the same may conformto the record of the case in the Patent Office.

Signed and sealed this-12th day of December, A. D. 1959.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

